<html>
<head>
    <style type="text/css">
        div {
            display: inline-block;
            border: 10px solid black;
            width: auto;
            text-align:center;
            font-size: 12px;
            font-family: "Microsoft YaHei";
        }
    </style>
</head>
<body>
    <!--<div><button style="margin-top:20px">First</button><button>Second</button><button>Third</button></div>-->
    <div>Third<div>Fourth</div></div>
</body>
</html>